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Found 36604 matches. Displaying 11-20
Eisner NL, Johnston C, Toonen S, Frost AJ, Janssens S, Lintott CJ, Aigrain S, Sana H, Abdul-Masih M, Arellano-Cordova KZ, Beck PG, Bordier E, Cannon E, Escorza A, Fabry M, Hermansson L, Howell SB, Miller G, Sheyte S, Alhassan S, Baeten EML, Barnet F, Bean SJ, Bernau M, Bundy DM, Di Fraia MZ, Emralino FM, Goodwin BL, Hermes P, Hoffman T, Huten M, Janicek R, Lee S, Mazzucato MT, Rogers DJ, Rout MP, Sejpka J, Tanner C, Terentev IA, Urvoy D
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Planet Hunters TESS IV: a massive, compact hierarchical triple star system TIC 470710327

We report the discovery and analysis of a massive, compact, hierarchical triple system (TIC 470710327) initially identified by citizen scientists in data obtained by NASA's Transiting Exoplanet Survey Satellite (TESS). Spectroscopic follow-up observations obtained with the hermes spectrograph, combined with eclipse-timing variations (ETVs), confirm that the system is comprised of three OB stars, with a compact 1.10 d eclipsing binary and a non-eclipsing tertiary on a 52.04 d orbit. Dynamical modelling of the system (from radial velocity and ETVs) reveal a rare configuration wherein the tertiary star (O9.5-B0.5V; 14-17 M-circle dot) is more massive than the combined mass of the inner binary (10.9-13.2 M-circle dot). Given the high mass of the tertiary, we predict that this system will undergo multiple phases of mass transfer in the future, and likely end up as a double neutron star gravitational wave progenitor or an exotic Thorne-Zytkow object. Further observational characterization of this system promises constraints on both formation scenarios of massive stars as well as their exotic evolutionary end-products.
Dolgetta A, Johnson M, Fruitman K, Siegel L, Zhou Y, McEwen BS, Kreek MJ, Milner TA
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Sex and chronic stress alter the distribution of glutamate receptors within rat hippocampal CA3 pyramidal cells following oxycodone conditioned place preference

NEUROBIOLOGY OF STRESS 2022 MAR; 17(?):? Article 100431
Glutamate receptors have a key role in the neurobiology of opioid addiction. Using electron microscopic immunocytochemical methods, this project elucidates how sex and chronic immobilization stress (CIS) impact the redistribution of GluN1 and GluA1 within rat hippocampal CA3 pyramidal cells following oxycodone (Oxy) conditioned place preference (CPP). Four groups of female and male Sprague-Dawley rats subjected to CPP were used: Saline- (Sal) and Oxy-injected (3 mg/kg, I.P.) naive rats; and Sal- and Oxy-injected CIS rats. GluN1: In both naive and CIS rats, Sal-females compared to Sal-males had elevated cytoplasmic and total dendritic GluN1. Following Oxy CPP, near plasmalemmal, cytoplasmic, and total GluN1 decreased in CA3 dendrites of unstressed females suggesting reduced pools of GluN1 available for ligand binding. Following CIS, Oxy-males (which did not acquire CPP) had increased GluN1 in all compartments of dendrites and spines of CA3 neurons. GluA1: There were no differences in the distribution GluA1 in any cellular compartments of CA3 dendrites in naive females and males following either Sal or Oxy CPP. CIS alone increased the percent of GluA1 in CA3 dendritic spines in males compared to females. CIS Oxy-males compared to CIS Sal-males had an increase in cytoplasmic and total dendritic GluA1. Thus, in CIS Oxy-males increased pools of GluN1 and GluA1 are available for ligand binding in CA3 neurons. Together with our prior experiments, these changes in GluN1 and GluA1 following CIS in males may contribute to an increased sensitivity of CA3 neurons to glutamate excitation and a reduced capacity to acquire Oxy CPP.
Caradonna SG, Einhorn NR, Saudagar V, Khalil H, Petty GH, Lihagen A, LeFloch C, Lee FS, Akil H, Guidotti A, McEwen BS, Gatta E, Marrocco J
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Corticosterone induces discrete epigenetic signatures in the dorsal and ventral hippocampus that depend upon sex and genotype: focus on methylated Nr3c1 gene

TRANSLATIONAL PSYCHIATRY 2022 MAR 16; 12(1):? Article 109
The genomic effects of circulating glucocorticoids are particularly relevant in cortico-limbic structures, which express a high concentration of steroid hormone receptors. To date, no studies have investigated genomic differences in hippocampal subregions, namely the dorsal (dHPC) and ventral (vHPC) hippocampus, in preclinical models treated with exogenous glucocorticoids. Chronic oral corticosterone (CORT) in mouse is a pharmacological approach that disrupts the activity of the hypothalamic-pituitary-adrenal axis, increases affective behavior, and induces genomic changes after stress in the HPC of wildtype (WT) mice and mice heterozygous for the gene coding for brain-derived neurotrophic factor Va166Met (hMet), a variant associated with genetic susceptibility to stress. Using RNA-sequencing, we investigated the genomic signatures of oral CORT in the dHPC and vHPC of WT and hMet male and female mice, and examined sex and genotype differences in response to oral CORT. Males under CORT showed lower glycemia and increased anxiety- and depression-like behavior compared to females that showed instead opposite affective behavior in response to CORT. Rank-rank-hypergeometric overlap (RRHO) was used to identify genes from a continuous gradient of significancy that were concordant across groups. RRHO showed that CORT-induced differentially expressed genes (DEGs) in WT mice and hMet mice converged in the dHPC of males and females, while in the vHPC, DEGs converged in males and diverged in females. The vHPC showed a higher number of DEGs compared to the dHPC and exhibited sex differences related to glucocorticoid receptor (GR)-binding genes and epigenetic modifiers. Methyl-DNA-immunoprecipitation in the vHPC revealed differential methylation of the exons 1(C) and 1(F) of the GR gene (Nr3c1) in hMet females. Together, we report behavioral and endocrinological sex differences in response to CORT, as well as epigenetic signatures that i) differ in the dHPC and vHPC,ii) are distinct in males and females, and iii) implicate differential methylation of Nr3c1 selectively in hMet females.
Mahdaviani SA, Fallahi M, Jamee M, Marjani M, Tabarsi P, Moniri A, Farnia P, Daneshmandi Z, Parvaneh N, Casanova JL, Bustamante J, Mansouri D, Velayati AA
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Effective anti-mycobacterial treatment for BCG disease in patients with Mendelian Susceptibility to Mycobacterial Disease (MSMD): a case series

Background: Post-vaccination BCG disease typically attests to underlying inborn errors of immunity (IEIs), with the highest rates of complications in patients with Mendelian susceptibility to mycobacterial disease (MSMD). However, therapeutic protocols for the management of BCG-osis (disseminated) and persistent BCG-itis (localized) are still controversial. Methods: Twenty-four Iranian patients with MSMD (BCG-osis or BCG-itis), followed from 2009 to 2020 in Tehran, were included in the study. Their medical records were retrospectively reviewed for demographics, clinical features, laboratory findings, and molecular diagnosis. The therapeutic protocol sheets were prepared to contain the types and duration of anti-mycobacterial agents. Results: BCG disease either as BCG-itis (33.3%) or BCG-osis (66.7%) was confirmed in all patients by positive gastric washing test (54.2%), microbial smear and culture (58.3%), or purified protein derivative (PPD) test (4.2%). The duration between BCG-osis onset and MSMD diagnosis was 21.6 months. All except three patients were initiated on second-line anti-mycobacterial agents with either a fluoroquinolone (levofloxacin: 15 mg/kg/day, ciprofloxacin: 20 mg/kg/day, ofloxacin: 15 mg/kg/day), aminoglycoside (amikacin: 10-15 mg/ kg/day, streptomycin: 15 mg/kg/day), and/or macrolide (clarithromycin: 15 mg/kg/day) along with oral rifampin (10 mg/kg/day), isoniazid (15 mg/kg/day), and ethambutol (20 mg/kg/day). Three patients showed a clinical response to rifampin, despite in vitro resistance. Fourteen (58.3%) patients received also adjuvant subcutaneous IFN-gamma therapy, 50 mu/m(2) every other day. At the end of survey, most patients (n = 22, 91.7%) were alive and two patients died following BCG-osis and respiratory failure. Conclusions: We recommend the early instigation of second-line anti-mycobacterial agents in MSMD patients with BCG disease.
Maguin P, Varble A, Modell JW, Marraffini LA
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Cleavage of viral DNA by restriction endonucleases stimulates the type II CRISPR-Cas immune response

MOLECULAR CELL 2022 MAR 3; 82(5):907-+
Prokaryotic organisms have developed multiple defense systems against phages; however, little is known about whether and how these interact with each other. Here, we studied the connection between two of the most prominent prokaryotic immune systems: restriction-modification and CRISPR. While both systems employ enzymes that cleave a specific DNA sequence of the invader, CRISPR nucleases are programmed with phage-derived spacer sequences, which are integrated into the CRISPR locus upon infection. We found that restriction endonucleases provide a short-term defense, which is rapidly overcome through methylation of the phage genome. In a small fraction of the cells, however, restriction results in the acquisition of spacer sequences from the cleavage site, which mediates a robust type II-A CRISPR-Cas immune response against the methylated phage. This mechanism is reminiscent of eukaryotic immunity in which the innate response offers a first temporary line of defense and also activates a second and more robust adaptive response.
Stoeckle MY, Adolf J, Ausubel JH, Charlop-Powers Z, Dunton KJ, Hinks G
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Current laboratory protocols for detecting fish species with environmental DNA optimize sensitivity and reproducibility, especially for more abundant populations

Analysing environmental DNA (eDNA) in seawater can aid in monitoring marine fish populations. However, the extent to which current methods optimize fish eDNA detection from water samples is unknown. Here, we test modifications to laboratory components of an eDNA metabarcoding protocol targeting marine finfish. As compared to baseline methods, amplifying a smaller proportion of extracted DNA yielded fewer species, and, conversely, amplifying a larger proportion identified more taxa. Higher-read species were amplified more reproducibly and with less variation in read number than were lower-read species. Among pooled samples, 20-fold deeper sequencing recovered one additional fish species out of a total of 63 species. No benefit was observed with additional PCR cycles, alternative primer concentrations, or fish-selective primers. Experiments using an exogenous DNA standard to assess absolute eDNA concentration suggested that, for a given proportion of a DNA sample, current laboratory methods for metabarcoding marine fish eDNA are near to maximally sensitive. Our results support the unofficial standard collection volume of one liter for eDNA assessment of commonly encountered marine fish species. We conclude that eDNA rarity poses the main challenge to current methods.
Chen J, Wang Q, Malone B, Llewellyn E, Pechersky Y, Maruthi K, Eng ET, Perry JK, Campbell EA, Shaw DE, Darst SA
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Ensemble cryo-EM reveals conformational states of the nsp13 helicase in the SARS-CoV-2 helicase replication-transcription complex

In their complex, the SARS-CoV-2 nsp13 helicase and RNA polymerase would translocate on RNA in opposite directions. Cryo-EM and MD simulations resolve this conundrum, suggesting an allosteric mechanism to turn the helicase on and off. The SARS-CoV-2 nonstructural proteins coordinate genome replication and gene expression. Structural analyses revealed the basis for coupling of the essential nsp13 helicase with the RNA-dependent RNA polymerase (RdRp) where the holo-RdRp and RNA substrate (the replication-transcription complex or RTC) associated with two copies of nsp13 (nsp13(2)-RTC). One copy of nsp13 interacts with the template-RNA in an opposing polarity to the RdRp and is envisaged to drive the RdRp backward on the RNA template (backtracking), prompting questions as to how the RdRp can efficiently synthesize RNA in the presence of nsp13. Here we use cryogenic-electron microscopy and molecular dynamics simulations to analyze the nsp13(2)-RTC, revealing four distinct conformational states of the helicases. The results indicate a mechanism for the nsp13(2)-RTC to turn backtracking on and off, using an allosteric mechanism to switch between RNA synthesis or backtracking in response to stimuli at the RdRp active site.
Biegler MT, Fedrigo O, Collier P, Mountcastle J, Haase B, Tilgner HU, Jarvis ED
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Induction of an immortalized songbird cell line allows for gene characterization and knockout by CRISPR-Cas9

SCIENTIFIC REPORTS 2022 MAR 14; 12(1):? Article 4369
The zebra finch is one of the most commonly studied songbirds in biology, particularly in genomics, neuroscience and vocal communication. However, this species lacks a robust cell line for molecular biology research and reagent optimization. We generated a cell line, designated CFS414, from zebra finch embryonic fibroblasts using the SV40 large and small T antigens. This cell line demonstrates an improvement over previous songbird cell lines through continuous and density-independent growth, allowing for indefinite culture and monoclonal line derivation. Cytogenetic, genomic, and transcriptomic profiling established the provenance of this cell line and identified the expression of genes relevant to ongoing songbird research. Using this cell line, we disrupted endogenous gene sequences using S.aureus Cas9 and confirmed a stress-dependent localization response of a song system specialized gene, SAP30L. The utility of CFS414 cells enhances the comprehensive molecular potential of the zebra finch and validates cell immortalization strategies in a songbird species.
Gruell H, Gunst JD, Cohen YZ, Pahus MH, Malin JJ, Platten M, Millard KG, Tolstrup M, Jones RB, Alberto WDC, Lorenzi JCC, Oliveira TY, Kummerle T, Suarez I, Unson-O'Brien C, Nogueira L, Olesen R, Ostergaard L, Nielsen H, Lehmann C, Nussenzweig MC, Fatkenheuer G, Klein F, Caskey M, Sogaard OS
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Effect of 3BNC117 and romidepsin on the HIV-1 reservoir in people taking suppressive antiretroviral therapy (ROADMAP): a randomised, open-label, phase 2A trial

LANCET MICROBE 2022 MAR; 3(3):E203-E214
Background The administration of broadly neutralising anti-HIV-1 antibodies before latency reversal could facilitate elimination of HIV-1-infected CD4 T cells. We tested this concept by combining the broadly neutralising antibody 3BNC117 in combination with the latency-reversing agent romidepsin in people with HIV-1 who were taking suppressive antiretroviral therapy (ART). Methods We did a randomised, open-label, phase 2A trial at three university hospital centres in Denmark, Germany, and the USA. Eligible participants were virologically suppressed adults aged 18-65 years who were infected with HIV-1 and on ART for at least 18 months, with plasma HIV-1 RNA concentrations of less than 50 copies per mL for at least 12 months, and a CD4 T-cell count of greater than 500 cells per mu L. Participants were randomly assigned (1:1) to receive 3BNC117 plus romidepsin or romidepsin alone in two cycles. All participants received intravenous infusions of romidepsin (5 mg/m(2) given over 120 min) at weeks 0, 1, and 2 (treatment cycle 1) and weeks 8, 9, and 10 (treatment cycle 2). Those in the 3BNC117 plus romidepsin group received an intravenous infusion of 3BNC117 (30 mg/kg given over 60 min) 2 days before each treatment cycle. An analytic treatment interruption (ATI) of ART was done at week 24 in both groups. Our primary endpoint was time to viral rebound during analytic treatment interruption, which was assessed in all participants who completed both treatment cycles and ATI. We used a log-rank test to compare time to viral rebound during analytic treatment interruption between the two groups. This trial is registered with ClinicalTrials. gov, NCT02850016. It is closed to new participants, and all follow-up is complete. Findings Between March 20, 2017, and Aug 14, 2018, 22 people were enrolled and randomly assigned, 11 to the 3BNC117 plus romidepsin group and 11 to the romidepsin group. 19 participants completed both treatment cycles and the ATI: 11 in the 3BNC117 plus romidepsin group and 8 in the romidepsin group. The median time to viral rebound during ATI was 18 days (IQR 14-28) in the 3BNC117 plus romidepsin group and 28 days (21-35) in the romidepsin group B (p=0.0016). Although this difference was significant, prolongation of time to viral rebound was not clinically meaningful in either group. All participants in both groups reported adverse events, but overall the combination of 3BNC117 and romidepsin was safe. Two severe adverse events were observed in the romidepsin group during 48 weeks of follow-up, one of which-increased direct bilirubin-was judged to be related to treatment. Interpretation The combination of 3BNC117 and romidepsin was safe but did not delay viral rebound during analytic treatment interruptions in individuals on long-term ART. The results of our trial could serve as a benchmark for further optimisation of HIV-1 curative strategies among people with HIV-1 who are taking suppressive ART. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd.